Figure 1From: pKa determination of oxysophocarpine by reversed - phase high performance liquid chromatography The typical HPLC chromatograms of oxysophocarpine eluted by the mobile phase of 15% ( v/v ) MeOH. (1 = pH2.2, 2 = pH2.5, 3 = pH 3.9, 4 = pH 5.0, 5 = pH 6.0, 6 = pH7.0, 7 = pH7.6.7, 8 = pH7.9, 9 = pH8.9).Back to article page